1. Field of the Invention
The present invention relates to an ion beam measuring device and a method of measuring an ion beam that are appropriate for an ion implantation apparatus.
2. Description of the Related Art
Methods for measuring the angle of the traveling direction of an ion beam have been known. In such a method, for example, a mask plate having small circular holes that allow a part of a ribbon-shaped ion beam to pass therethrough is arranged on the upstream side of a beam monitor. In another method, a flag moved by a translation mechanism is used, and the flag has first and second shapes that enable the measurement of the angle of the ion beam. The first shape is the shape of a perpendicular slot, and the second shape is the shape of an inclined edge.
In an ion implantation process, the angle of an ion beam to be implanted is controlled or managed. Particularly, in the ion implantation of a high energy region, the angle has been desired to be controlled or managed with high precision. However, in such a region, generally, the beam current is small, and accordingly, it is not easy to perform high-precision measurement. As described above, when the passage of a beam is restricted by the small circular holes of the mask plate, the beam current is extremely small, and accordingly, it may be difficult to perform measurement with required precision. In addition, it is complicated to measure beam angles of two directions perpendicular to the traveling direction of an ion beam by using the movable inclined edge.